*{
    margin: 0;
    padding: 0;
}

#div1{
    width: 200px;
    height: 200px;
    border: 1px solid #0cc;

    background: url('../img/user10.jpg') no-repeat;
    background-size: 150px auto;
}

#div2{
    width: 400px;
    height: 400px;
    border: 1px solid #0cc;

    background: url('../img/slide-1.jpg') no-repeat;
    background-size: cover;
}

#div3{
    width: 200px;
    height: 200px;
    background-color: rgb(0,0,0,0.5);
    position: fixed;
    top: 0;
    left: 0;;
}

#div4{
    width: 600px;
    height: 400px;
    background: url('../img/slide-1.jpg') no-repeat;
    background-size: cover;
    filter: blur(5px);
}